ch 20 lymphatic system/lymphoid tissues Flashcards
what is the function of the lymphatic system
picks up fluid that is lost by blood capillaries, and is eventually returned to circulation
what does lymphatic system consist of
lymph vessels, lymph, lymph nodes
lymphoid organs
provides structure. basis for immune system, monitors body for infection, houses phagocytic cells nd lymphocytes
what do the lymphatic vessels do
picks up proteins containing interstitial fluid that is not reabsorbed by blood capillaries, intertwined w blood capillaries to return things fast
what is interstitial fluid
fluid between organs
what is the fluid called once it enters lymph vessel
lymph
lymph vessels move fluid where
toward the heart
lymph capillaries
dead ended vessels that weave through capillary beds, very permeable because of 2 structures
what 2 structures make the lymph capillaries highly permeable
loosely aggregated endothelial cells in capillary walls and forms a flap that opens
anchoring filaments which increase interstitial fluids and pulls on anchoring filaments.
lymph capillaries
allow large protein intake, become more permeable during infection, sent pathogens to lymph node for immune system destroy
lacteals
special lymph capillaries that move fats, which are usually insoluble and must attach to protein to be absorbed, from small intestine to blood
lymph capillaries drain into
larger lymph vessels through a cycle
collecting lymph vessels, lymphatic trunks, lymphatic ducts
collecting lymphatic vessels
superficial in skin, travel by veins. deep in trunk, in arteries. saves space this way
lymphatic trunk
drainage areas resulting from collecting vessels uniting. there are-
lumbar trunk which drains legs, bronchomediastinal trunk drains thorax, subclavian trunk drains arms and superficial thoracic wall, jugular trunks drain head. n neck and only ONE intestinal trunk drains digestive organs
lymphatic ducts
where lymphatic trunks will drain into, both L and R ducts empty into junction at internal jugular and subclavian. empties into veins on according side.
the 2 lymphatic ducts
R lymphatic duct- drain lymph from right upper limb, right head side, right thorax, smaller than below
Thoracic duct- drains any part of body that is not drained by right lymphatic duct. begins and cistern chyli, L upper limb L thorax L lumber trunks and intestinal trunk comes here
how is lymph transported and why is it hard to transport
lymph doesn’t have pump, and walls are so thin with large lumen. so in order to go back to circulation bc there is no pump or heart business, 4 solutions
smooth muscle ein large vessel helps push lymph, respirator pump when lungs change in size when breathing helps pump and valves prevent back flow, nearby arteries can encourage circulation, physical movement by skeletal muslce
why is it important to move infected body region once infected
increases rate of removal of inflammatory material, lymph will circulate more and make immune system notice
what happens if the lymph vessels/nodes are blocked
localized edema, no where for fluid to drain. lymphedema occurs. cancer can cause this as well as obesity
immune system cells and support cells that form lymphoid tissue
lymphocytes, defense cells
T lymphocytes or T cells
B lymphocytes or B cells
all produce antibodies that protects body from non-body antigens
T cells
helper T cell manages the immune response, assists in maturing B cells, macrophages
killer T cells are cell destroyers (cytotoxins) and kill off virus infected and cancerous cells
What kills T cells rapidly, affectong immune system
HIV
B cells
produce plasma cells, which secrete antibodies into blood. antibodies are red flags and mark it for destruction
macrophages
defense cell, phagocytizes (consumes) large substances and helps activate T cells (in extreme situations)
dendritic cell
cells that escort red flag cells to lymph nodes, dendritic cells put them on display they are the NARCs. wanders around looking for what doesn’t belong lol
reticular cells
supporting cells, produces stroma which supports cell types in lymphoid tissue/organs.
stroma
mesh of interconnected tissue cells that supports WBC
lymphoid tissue
houses lymphocyte cells, allows proliferation of them, and surveillance point for lymphoid cells
what is lymphoid tissue made of
reticular connective tissue, but not in the thymus
lymphoid tissue types
diffuse lymphoid tissue, lymphoid nodules
diffuse lymphoid tissue
widespread, each organ has its own immune response, reduces risk of infection, larger collections are in mucous membranes
lymphoid nodules
tightly packed lymphoid cells and reticular fibers, usually forms part of larger lymphoid organs, antibodies r produced here to prevent infection. many nodes r here in connective tissue covering.
